利用荧光差异显示技术分离的家蚕抗NPV相关基因s3a

通过荧光差异显示技术，分析了家蚕Bombyx mori对BmNPV抗性品系NB、感性品系306和近等基因系306NNZZ添毒和未添毒处理区的基因表达的差异。根据差异显示的结果克隆了一条702 bp长度的cDNA片段，并用Northern blot进行了验证。该序列经过NCBI EST库的同源性比较获得了电子延伸。延伸后的序列用特异引物进行RT-PCR扩增获得了一条782 bp的序列，拼接后基因cDNA序列全长为827 bp，推导的氨基酸序列与草地夜蛾Spodoptera frugiperda S3A同源性最高达97.7％；其次是烟芽夜蛾Heliothis virescens S3A，同源性为94.0％；与黑腹果蝇Drosophila melanogaster S3A同源性为75.3%。比较结果显示这是一个新的家蚕基因，定名为家蚕s3a基因。本实验获得的s3a基因在家蚕感性和抗性品系以及添毒处理和未添毒处理中都具有差异表达，其中在抗性品系和近等基因系中的表达高于感性品系，在添毒处理中的表达高于未添毒组。因此推测它是一个与家蚕抗BmNPV相关的新基因。

Fluorescent differential display analysis of the gene s 3a related to NPV resistance in Bombyx mori L.

Using fluorescent differential display (FDD) technique, the differential expression of genes related to BmNPV resistance in highly resistant strain NB, highly susceptible strain 306 and near isogenic line 306NNZZ of the silkworm, Bombyx mori L. was analyzed. Based on the differential display bands, a 702 bp fragment named C18 (702) was cloned and confirmed by Northern blot hybridizations. The sequence was then electrically extended based on homology comparison with NCBI ESTs, and further confirmed by RT_PCR using specific primers. A novel gene was characterized and revealed to encode a putative BmS3A protein. The gene had 97.7% homology to Spodoptera frugiperda S3A, 94% homology to Heliothis virescens S3A and 75.3% homology to Drosophila melanogaster S3A, and was named B. mori s3a (Bms3a). It had higher expression in the highly resistant strain and near isogenic line than in the highly susceptible silkworm strain, and it also had higher expression in BmNPV treated strains than untreated strains. The results suggested that Bms3a is involved in silkworm BmNPV resistance.